There should be no need to paint the hull. A good print is watertight and looks much better without paint. If you are unsure, you can test it in the bath tube. But try to get, as always, a best possible print.
The dimensions are in "Instructions" further down:
sterntube 4/3 mm, 120mm long (brass)
I open the hole for the stern tube on both ends very carefully with a smaller drill first and than with a small round file.
Congrats to the already succesfully printed bow. It is not alway so easy to get it with a proper top.